Conventionally, a wide variety of sample analyzers for analyzing cell components included in a sample such as blood or urine have been developed. For example, U.S. Pat. No. 7,580,120 discloses a blood analyzer for counting cell components of blood after sorting the components into different groups such as red blood cells, white blood cells, and platelets. According to the blood analyzer, a measurement specimen prepared by mixing a blood sample with a reagent suitable for a particular measurement item is poured into a flow cell, and a liquid flow in the flow cell is irradiated with light from a light source, so that light generated by the irradiation of the light is received by a light receiving element. Then, the received light is photo-electrically converted to obtain an electrical signal, and the blood component can be analyzed by observing variation of the obtained electrical signal.
Apart from the above-mentioned analyzer which optically analyzes the sample, there is a sample analyzer which utilizes an electrical resistance, wherein cell components of a sample such as blood or urine are analyzed by observing variation of the electrical resistance. In either of the analyzers, an analysis result thereby obtained is largely affected by a sensitivity of a sensor, such as light receiving element or resistance sensor (current sensor).
To suitably retain the sensitivity of the sensor, sensors of the conventional sample analyzers are needed to be periodically adjusted. To adjust the sensitivity, an analysis result obtained by actually analyzing a sample obtained from a patient is used. The sensitivity is adjusted so that an analysis result of a sample, which is very likely to demonstrate a particular result, falls within a predetermined range.
In the conventional sample analyzer disclosed in U.S. Pat. No. 7,580,120, it is necessary to stock a plurality of samples whose analysis results fall within a predetermined range, that is, a plurality of samples having a homogeneous characteristic. However, most of the samples such as blood and urine are, in fact, not homogenous, and it imposes an excessive load on a user of the analyzer to search analysis results of any suitable samples in a huge volume of analysis results.